Despite the urban myth reinforced by many a daytime talk show, researchers writing in Trends in Ecology & Evolution on April 5 say the emerging evidence consistently indicates that very few fathers have unknowingly raised children who were not biologically their own. The collective evidence for low rates of extra-pair paternity (EPP) challenges the notion that it pays, evolutionarily speaking, to sleep around, the researchers say.
"Media and popular scientific literature often claim that many alleged fathers are being cuckolded into raising children that biologically are not their own," said Maarten Larmuseau of KU Leuven in Belgium. "Surprisingly, the estimated rates within human populations are quite low--around 1 or 2 percent."
Those rates apparently haven't changed much either, despite the fact that people in the past didn't have access to modern contraceptives.